Holly J. first started to develop a crush on Declan before she discovered his affair with Jane Vaughn. After Jane ended her fling with him to be faithful to Spinner, Declan set his sights on Holly J. The two then began a relationship, despite Declan's reputation as a player preceding him, and Holly J.'s reluctance to date him. Holly J. briefly broke up with him when she became tired of Fiona's jealousy towards her, but they quickly reconciled and their relationship lasted well into the tenth season, before Holly J. ended it permanently after she felt Declan wanted to "own" her. Although she dated Sav Bhandari throughout the rest of Season 10, she still harbored feelings for Declan.
In Wanna Be Startin' Somethin', Holly J. accidentally hits Declan's car on the way to school, but he is cool with it and says it's fine. Holly J. begins to develop a crush on Declan.
In Waiting for a Girl Like You, it's Matchmaker Week at Degrassi and Declan sets his sights on Holly J. He tries to win her over by placing a rose and magnet letters that spell Friday on her locker. When she comes back from doing morning announcements she sees him leaning against her locker, playing music from his cell. He then asks her out but she declines. In computer class, he made a people profile for Holly J. and she liked it. When the results were delivered at lunch later that day Holly J. gets matched with Declan. He eats with her and tells her the story about him meeting the Dalai Lama. His girlfriend Trish, who he was about to break up with, walks up and yells at Declan then tells Holly J. that he is probably going to tell her his fake stories like meeting the Dalai Lama. Holly J. gets up and leaves which causes Declan to stand up quickly, accidentally spilling his lunch tray all over his pants.
The next day at lunch Declan takes Holly J. to the Music Room. He locks her in the recording booth and he keeps her in there until she stops yelling. After she calms down, he tells her that she is the one girl that he really likes and wants to go out with. Another student walks in and he unlocks the door. When she tells him that on Friday she'll have to babysit at the school, Declan surprises her there and plays with the kids. Afterwards, they go out for mushroom pizza and the two share their first kiss.
In Somebody, Holly J. gets a mentorship paper; she is ecstatic and tells Declan. They decide to skip 4th period and take silly pictures at a clothing store. At the Dot he tells her that the judge is his mom and will be interviewing Holly J. When Holly J. is being interviewed, she tells Declan's mom that her and Declan are dating. Declan's mother Laura Coyne disapproves of the relationship. Holly J. gets angry and walks out. But, Holly J. gets picked for the mentorship at the ceremony, and she is calm and professional. Then Declan appears behind the stage and she goes back with him. They start flirting, and soon begin making out. She unbuttons her dress halfway, and he continues kissing. But when Holly J.'s name is called, they pull the curtain back and take a picture of her with her dress halfway unbuttoned, her bra showing and her hair down. She is extremely embarrassed and runs off.
Ms. Hatzilakos, Mrs. Coyne, and Mrs. Sinclair have a meeting with Holly J. and Declan. They all agree that Holly J. and Declan shouldn't see each other and forbid them to be together. Declan likes the idea of sneaking around, but Holly J. wants to be open about their relationship. Holly J. wants to be with him so she confronts him and tells him that he should've opened his mouth, since he still wants to be with her too.They end up getting caught together again on the school camera, and they have another meeting with Ms. Hatzilakos, Mrs. Coyne, and Mrs. Sinclair. They are very surprised, and they still don't want them to go out. Declan stands up to them and says that they will be together, no matter what. He and Holly J. storm out of the office. They talk and Declan lifts her up and spins her around, kissing her.
In Heart Like Mine (1), Holly J. is seen being friendly with Marco Del Rossi. She and Declan are excited that he'll be their student teacher since he's their friend. When he starts assigning homework for their class, Holly J. and Declan take advantage of Marco to get out of assignments. They tell him they won't have to do it because they are busy. Marco is upset but he lets them slide this one time but tells them next time, they cannot. When he assigns an essay due in 2 days he makes Holly J. and Declan do it. At the basketball team victory party, Mr. Perino tells Marco that he has to stop letting Holly J. and Declan get away with stuff and says if he doesn't make them do it, he will be fired. So Marco confronts them and tells them that they have to do the assignments no matter what. Holly J. is irritated and texts Marco telling him that she thought they were friends. Later on, Holly J. and Declan agree to do the work, and Marco is happy.
In Why Can't This Be Love (1), Holly J. sets up the gym for the prom and gives advice to Anya who is worried that Farrah Hassan, Sav Bhandari's arranged future wife, will steal him away. She goes to prom with Declan and has a great time. The next day, Anya tells her that she had unprotected sex with Sav and that she could be pregnant, and Holly J. tells her that there was a condom machine in the bathroom. Holly J. assumes Anya is taking the pill and says she doesn't have to worry, but Anya tells her that she isn't on the pill. Holly J. is left shocked and speechless.
In Innocent When You Dream, Holly J. enjoys reading Clare Edwards' "Madame Degrassi's" fan-fiction posts. She shows Declan the posts and he reads them. After Clare kisses Declan's neck, Holly J. confronts her. Clare confesses, apologizes, and says that she is a "pervert," but Holly J. says it's all a part of puberty. She tells Clare that she is a very good writer and says if it stops her from wanting to kiss Declan, then she should continue writing, but warns Clare that if she touches her boyfriend again, she will destroy her. Declan walks in and asks if everything is okay, and both say yes.In Keep On Loving You, Holly J. and Declan have been going out for 3 months and feel that it's time to take it to the next level. They want to have sex. Before making love, Declan gives Holly J. his grandmother's special bracelet. Holly J. is touched and tells him that she loves him. Declan doesn't say it back, much to Holly J.'s dismay, but they still have sex. The next day at school, Holly J. tells Jane at lunch about Declan not telling her that he loves her. Jane tells Holly J. that she doesn't have to worry about it, and that she's sure Declan loves her and he'll tell her when he's ready.
When Declan is walking to play practice, Holly J. talks to him and asks him if he loves her because he didn't say it back the other night. Declan tells her it's not that simple and Holly J. is worried. At play practice, Fiona comes to visit Declan. Declan tells her that he is nervous to tell her since last time. Fiona laughs and tells him that he's a silly boy.
The next day, Holly J. sees Fiona in the school library and tells her to give Declan's bracelet back since he doesn't love her. Fiona laughs at her and says that it's their grandmother's bracelet and Declan only gives it to the people he truly loves. Holly J. asks why he couldn't say it then. Fiona tells her that Declan had a girlfriend once and he told her that he loved her and then she cheated on him. He was scared and doesn't want that to happen again. Holly J. takes the bracelet and goes to find Declan. When she finds him, they talk and make up.
Later on, Fiona and Declan's mother comes and tells them they are going back to Manhattan. Fiona is excited and hugs her mom. Declan, however, is upset and doesn't know how he's going to be able to tell Holly J. Later that day, Holly J. sees Fiona's Facerange status and realizes what is going on. The morning of the play Declan and his mom are talking and Declan tells her that he loves the school and doesn't want to go home. Holly J. over hears this while walking in. Crushed, she asks Declan's mom if she can visit. Mrs. Coyne reluctantly says she can visit anytime.
Before directing the play, Declan hacks Holly J.'s email account and emails Holly J.'s mentorship video to a Manhattan internship. Throughout the play's songs, Holly J. and Declan are cuddling each other. The musical closes successfully, and Declan tells Holly J. he loves her. She smiles and kisses him. At the Dot, Holly J. gets a text about an internship in Manhattan over the summer. Declan reveals that it was all his doing. She is happy and they embrace each other.
In Degrassi Takes Manhattan, Holly J. is excited to go to New York over the summer with her boyfriend Declan. When Declan is telling Holly J. about their trip they are seen kissing on a chair, then they fall off the chair still kissing. After, school is finally let out, Declan invites everyone over to his house for a pool party. Spinner is there, and while Holly J. and Jane are changing in their bathing suits he overhears them talking about how breaking off Jane's affair with Declan helped Holly J. because she loves him. After, walking out Spinner confronts Jane and breaks up with her, tells Holly J. to shut up and punches Declan. Holly J. tries to help Declan and comfort Jane. Seeing Jane upset, Holly J. asks her to go to Manhattan with her and Declan for the summer. Jane accepts. The next day they're off and they go to Manhattan. When they get there Holly J. is surprised on how big their Manhattan home is. After, they leave Fiona off at the house, because she's tired and doesn't want to move, and they go site seeing and shopping. Later, Declan and Holly J. have reservations for a restaurant and Fiona looks jealous.
The next day, Holly J. is walking in the city to go to her TVM internship, and she walks into Jay Manuel who gives her advice. After, she goes in to see her boss, Kristin. She decides to make the most, of it and introduces herself to her. She gets a clever nickname, initial because Kristin likes the J in Holly J. She also is given a banana each day because Kristin loves potassium. A few moments later, Holly J. learns that Declan and Fiona are the city's power siblings after Fiona stops by at TVM to say hi, and get an internship too.
The next day, after finding out that Jane has become the lead singer of the hit band, Flashin' Midnight, Holly J. is asked to do research and stay late at TVM. She does so and ends up not going to the opera with Declan. He ends up going with Fiona. The next day at work, Holly J. is talking to Fiona and then Fiona gets mad and tells her that this is her city and she owns this, and she put up with her at Degrassi for too long. They get into an argument, and while walking in the hallway, Holly J. tells Fiona to look away, and then she locks Fiona in the copy room.
That day, while after interviewing Jane on the show, Holly J. notices that Fiona is all distraught and managed to get out of the copy room. Declan confronts her. Holly J. tries to tell Declan that Fiona started it, but Declan didn't understand why Holly J. did that to his sister. Walking away, Fiona glares at Holly J.
Later, Declan sits them both down and tells them that they need to make up because he wants to spend the whole summer with the both of them. They seemingly make amends, and hug each other. Fiona then suggests that they have a party so Holly J. can meet some of their New York friends. That night, Holly J. comes down the stairs in a stunning green dress, and talks to Declan. Fiona then introduces her to Declan's ex-girlfriends, and they tell Holly J. that Fiona likes Declan single, and that her relationship with him won't last. Holly J. is upset, but Declan proves to her that he is in love with her by kissing her. Fiona is drunk and jealous, so she pulls Declan away from Holly J. Holly J. gets angry and tells Fiona that her jealousy is quite inappropriate, Fiona tells her "You want inappropriate?" and kisses Declan. Everyone is shocked, and Declan pushes her away; Fiona faints. Holly J. is angry and tells Declan she is tired of coming second to Fiona. Jane and Holly J. leave. Fiona smirks while watching them walk away.
The next day, Declan tells Fiona that there is something wrong with her and that she is so jealous to a point that it's weird. Fiona breaks down into tears telling Declan that he is so inconsiderate, but then he tells her that he can't have the summer with her being jealous of Holly J. and him, so he tells her that she's going to the Hamptons with their Aunt Kate. Fiona tells Declan that she hates him. Declan apologizes to Holly J., by going live on air at TVM while Holly J. is listening, and then Holly J. turns around to find Declan standing there, asking for another chance. Holly J. says yes and they reconcile. Jane then finds them and tells them that Spinner is getting married to Emma Nelson, and that she wants to get there before it's too late, hoping to get him back. They both agree to drive her there. While stopping for gas, Declan and Holly J. agree that this is too crazy, so they decide to stall. While playing in a batting cage, Jane is frantic, so she takes the car and leaves Declan and Holly J. behind. Holly J. and Declan are upset, but end up taking a ferry to get to Toronto. They arrive and Emma is actually happy to see them and invites them to come to their wedding. They celebrate with everyone and go back to Manhattan. Fiona is just about to leave Manhattan to go back to the Hamptons with her mom.
In What a Girl Wants (1), after Declan's mom threw Holly J. a huge goodbye party, it was time for Holly J. to leave. After Declan says goodbye to Holly J., she tells him it is only 8 months away until it's the summer time again, and then they can go to Yale and finally be reunited. While saying goodbye, they make out, and he gives her a S.A.T. practice book. Declan is later seen video chatting with Holly J., before their conversation is interrupted by her mother.
In Breakaway (1), Holly J. gets a call from Declan, and they talk about Fiona—Holly J. tells Declan to trust Fiona and be there for her, like a good brother. Declan chooses to take Holly J.'s advice.
In Breakaway (2), Declan and Holly J. video chat and Declan is bambuzzled with a ton of questions. She asks him about if there are any good colleges out there like Yale. Declan gives her advice, and Holly J. ends up leaving the chat. Declan does not know that Holly J. stole money from Fiona in order to pay a private tutor.In Try Honesty (1), Declan asks Holly J. if she wants to go along with him on a road trip to Yale University, but she is unable to because she is busy with school work, and can't pay for the last minute airfare. While in math class Fiona asks Holly J. if she wants to go shopping after school, but can't because she has a job interview. Holly J. later decides to go shopping with Fiona after the interview and uses her emergency credit card. When they arrive at Fiona's condo, Holly J. uses her laptop to e-mail Declan. Upon seeing that he is not online, she goes to his profile and sees pictures of him with a girl named Tinsley Wharton and begins to get suspicious. Later she e-mails Declan to tell him that she decided to go on the road trip with him. While looking at flights online, Declan calls her and he tells her that it may not be such a good idea for her to come and she shouldn't waste the money. He then hangs up and goes off with Tinsley to fencing practice. Shocked she closes and laptop and says he's cheating on her. Later, Holly J. tells her mom about Declan cheating on her and that she isn't sure she wants to go to Yale anymore. Her mom comforts her and tells her that she's should go to Yale for her education, not to live out her fairy tale fantasy. That night she calls Declan only to get his voice mail. She decides to leave him a voice mail telling him how she feels and that she can't handle their long distance relationship and breaks up with him. The next day, when she is supposed to meet up with Fiona at The Dot before school, Declan is there instead to surprise her.
In Try Honesty (2), Holly J. and Declan sit at the Dot and talk to each other. Declan tells her how he didn't want her to go to Manhattan on the trip, because he and Fiona planned for him to come visit. Holly J. is happy and explains why she thought he was cheating, and to ignore her angry voicemail that she left on his phone. Declan didn't know about the voicemail, because his phone was off. He checks it, and after hearing it, he laughs and they continue to talk. On a taxi ride to school, Declan tells Holly J. he missed her and about his new school, also giving her a necklace. At lunch the next day, Declan surprises Holly J., sitting down with her. He brings up her financial problems, and she starts to think that he is buying her love with money. From her discussion with her mother the night before, Holly J. becomes pissed, because she feels like he is pressuring her. She yells at him and he leaves. A few days later in a taxi cab with Holly J., he continues talking about buying her stuff, and she snaps at him. He is confused, and Holly J. tells the driver to stop driving. They fight, and she states him that she feels gross, like Declan is buying her love. Holly J. gives Declan the necklace, and tells him they should take a break from each other. They both start crying and separate from each other.
In Love Lockdown (1), Declan's back from New York after being nominated for a Grundy Award. He notices Holly J., who is surprised to see him. He wants to go to lunch with her which Holly J. accepts. Later, Sav and Holly J. are walking in the hallway when he tells Holly J. to spend time during lunch with him to prepare for the Grundy Award. Holly J. admits she is having lunch with Declan. Sav looks surprised and warns Holly J. that it might be Declan's ploy to get her back. Holly J. promises Sav that she’s happy with him and has no intention in getting back together with Declan, and that he is flying to New York the very next day. Holly J. then kisses Sav on the cheek and they walk together. Later during lunch, Declan tells Holly J. that he took what she said about him using money to fix his problems to heart and has started a charity for kids. Holly J. reveals that she is in a relationship with Sav and that they will end it after their graduation. That night Sav accompanies Holly J. to the Grundy’s and Declan comes and takes the seat next to Holly J. from Fiona. Later Declan won a Grundy and is dedicating the award, and apparently his entire life, to Holly J. The Coyne's throw a party back at Fiona's condo and Holly J. and Sav agree to go. Declan has a plan to get Holly J. away from Sav and it comes in the form of playing with an iPad. With Sav distracted with his fancy toy, Declan makes his move and tells Holly J. that he loves her and wants her back. Holly J. tells Declan that she’s happy with Sav and doesn’t want to be back together with Declan. Declan tells Fiona that his plan didn’t work. All of a sudden Fiona goes from sober to drunk in one sip. Holly J. stays to help take care of a drunk Fiona, giving Declan a chance to make his move. Later after putting Fiona back to sleep, Declan goes on kissing Holly J.'s neck, but Holly J. seems to be denying him and says "We shouldn't be doing this.", but Declan doesn't listen and tries to kiss her lips and eventually she kisses him back and the credits roll.
In Love Lockdown (2), after Holly J. and Declan have sex, they hug and she goes home. The next day, Declan thinks Holly J. is avoiding him, and questions Sav about her after running into him in front of the school. He asks Sav to tell her to call him and a confused Sav says he will. At school, Fiona excitedly asks Holly J. about what happened last night between her and Declan. Holly J. confesses that she felt pressured into having sex with Declan and regrets last night. While at work, Declan visits Holly J., who heard from Fiona that she actually didn't want to have sex with him the previous night. Holly J. tells Declan that she is confused about the entire situation and tells him to leave.
The next day, Holly J. is confronted by Sav, who is worried about her. She assures Sav that she is fine and that she will see him in Physics. After he leaves, she checks the Yale website and discovers she had been accepted. Meeting Fiona, Holly J. asks where Declan is and is surprised when Fiona says he is leaving to go back to New York. Holly J. hurriedly leaves school and visits Declan before his flight leaves. She tells him that she made it into Yale, and that they'll both be seeing each other, considering Declan will be attending Yale as well. Declan apologizes and tells her that he is sorry for what happened. Holly J. gives him a final goodbye, for now, and walks out the door, leaving Declan behind.
In Halo (2), Holly J. admits to Sav about what happened between her and Declan while he was visiting. She tells Sav it was a mistake, a massive one, but that she wants to be with him, not Declan. Despite this, Sav tells her that mistake sex doesn't just happen and he breaks up with her.
In Chasing Pavements (2), Holly J. admits to Fiona that with Declan, she felt like they could do anything together, and that being in love makes you feel like you have super powers. Holly J. admits that when she found out she was sick, it was hard for her not to call Declan.
In Dead and Gone (1), while Holly J. is in the hospital recovering from a kidney transplant, it is shown that Declan has sent her some "get-well-soon" flowers.
In Searching for Sinder3lla, Declan becomes interested in the girl ("Sinder3lla") who was at the computer before him, calling her the "girl of his dreams". The mystery girl and him have similar interests and hobbies, which is why he is so interested. After a suggestion from Sav, Declan goes to check under the girl's account details, but unfortunately for him, the session had timed out. He enlists Sav's help to find her, which involve searching the Internet with the niner's help and talking to Chantay and Holly J.
Declan and Sav bicker over who is going to be the one to ask Chantay, as neither want to do it because they both have girlfriends. Ultimately, Sav ends up asking about her, and Chantay misinterprets his intentions, though Declan reveals it is for him. Holly J. says it is a little desperate, asking how a screen shot can be compelling. Declan answers that he felt he should at least try and meet her since they share similar interests. Holly J. and Chantay tease him, saying his girl could really be the lunch man Roger. Holly J. and Declan are left alone. Declan tells Holly J. to just forget about the Sinder3lla stuff, and Holly J. promises that they won't say a word to Roger. Dropping her pencil bag in the process of leaving, Declan kneels down and picks it up, meaning to give it back to her. However, the words "Sinder3lla" are on the pencil bag, and Declan comes to the conclusion that Holly J. is his dream girl. He looks up, trying to find her, but Trish re-appears, covering his eyes. She gives Declan a hug, but over her shoulder Declan stares after Holly J.
In Good Times, Anya is angry with Sav since he helped hook Holly J. and Declan up, which ruined her English project, as they can't stop making out. Later, Holly J. and Declan walk into the room. Jane greets them, and Bruce says that "The Queen and King" have arrived. Jane says to the two if they have come to bother someone they are dating, will date, or have dated, then to please move along, and Holly J. is surprised Jane is giving up an audience, as she likes to perform. Declan comments, "Oh, you noticed, too?" They then sit with the others.
In Forgetting Sav Bhandari, Declan appears in Anya's vision of the future as Holly J.'s date to the play.
- First Relationship:
- Second Relationship:
- Declan-Jane Relationship
- Declan-Trish Relationship
- Declan-Clare Friendship
- Declan-Tinsley Friendship
- Sav-Holly J. Relationship
- Holly J. lost her virginity to Declan in Keep On Loving You.
- They were both kissed by Declan's twin sister Fiona Coyne.
- Declan's final line was spoken to Holly J. ("Goodbye, Holly J.")
- They both cheated on their significant others with each other: Holly J. on Sav Bhandari with Declan, and Declan on Trish with Holly J.
- They both attend Yale University.
- There is speculation that they are back together at University, although this is not confirmed.
- Holly J. is best friends with Declan's sister, Fiona Coyne.
- Declan's sister, Fiona Coyne had a crush on Holly J.
- Declan's sister Fiona was at first rivals with Holly J., but later became best friends with her.
- Aislinn Paul favors this couple.
- Holly J.'s friend, Jane, had an affair with Declan while she was in a relationship with Spinner Mason, Holly J.'s former crush.
- It is widely controversial among fans whether or not Declan raped Holly J. in Love Lockdown (1) since she repeatedly said no and Declan continued kissing her anyway. Some fans, however, don't consider it rape since Holly J. appeared to give in to his advances instead of continuing to fight him. This, though, is open for debate.
- In the Degrassi Mini Good Times, Bruce referred to them as the King and Queen.
- They were both members of the Degrassi Drama Department.
- They were both fans of The Economist, The Daily Show, Roald Dahl and James Bond movies.
- Chantay has referred to them as a "power couple".
- Declan's mother Laura Coyne initially disliked Holly J. but she eventually became very fond of her due to her support of Fiona during her struggles with alcoholism.
- Declan: "You have to trust me Holly J. I don't normally try this hard, and I am terrified right now. So would you please give me another chance?" - Waiting For a Girl Like You
- Holly J.: "With Declan, I felt like we could do anything together. Being in love makes you feel like you have super powers." - Chasing Pavements (2)
- Holly J.: "You're a good guy."
Declan: "Not half as good without you." - Love Lockdown (1)
- Declan: "Now that's a girl worth fighting for."
Sav: "Holly J. Sinclair? You have health insurance, right?" - Waiting for a Girl Like You
- Declan: "I couldn't wait."
Holly J.: "For what?"
Declan: "To spend every possible moment with you." - Waiting for a Girl Like You)
- Declan: "We wouldn't have to sneak around if you wouldn't keep us apart, so the new plan is: we're doing this!" - Somebody)
- Holly J.: "Declan, you're the right person, and this is the right time. I love you." - Keep On Loving You
- Holly J.: "Just know that I will never break your heart."
Declan: "How'd I get so lucky?" - Keep On Loving You
- Declan: "I'm calling because the girl who means more to me than anything won't take my calls. Holly J., the way Fiona acted last night made everything clear. I promise the rest of the summer will be everything you ever imagined. Take me back, please?"
Holly J.: "Well, this is your last chance." - Degrassi Takes Manhattan